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Godfrey, Daniel. "Synthesis, analysis and characterisation of CuFeS2(s) towards superior, green Cu(aq) leaching." Thesis, Imperial College London, 2016. http://hdl.handle.net/10044/1/55165.
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Efforts to decrease reliance on traditional high-consumption CuFeS2(s) pyrometallurgy, have focused on delivering hydrometallurgic solutions to the beneficiation of sulfide ores. Ionic liquids (IL) have been proposed as a potentially higher performance and more benign alternative to conventional acid-SO42-(aq) for CuFeS2(s) dissolution, although the sheer number of IL variants complicates the search for the most efficient systems. This study focuses on Cu2+(aq)-leaching performance in hydrogensulfate IL(aq)-CuFeS2(s) systems and comparisons with equivalent acidity conventional-SO42-(aq) references. A single commercial CuFeS2(s) ore source is used throughout. A combinatorial strategy is applied to low-volume scale identification of high performance IL(aq) lixiviant systems. Implementation of a high performance, flexible automated workstation is presented with broad applicability to study of acidic-CuFeS2(s) dissolution. Electrochemical ASV is demonstrated to be an effective screening tool for [Cu2+](aq) extraction quantification, as verified by ICP-AES measurements throughout. Successfully ASV modifications are described; most notably a procedure for automated in situ electrochemical monitoring of 120 mL-scale CuFeS2(s) dissolution. High accuracy reconstructed (continuous) Cu2+(aq) extraction profiles offer precise rate determinations and treatment of previously unconsidered profile features. Application of the robotic custom instrument demonstrates high-throughput electrochemical screening of IL(aq) sample arrays with minimal consumption and precise [Cu2+](aq) measurements. Proof-of-concept screening assays find >102 difference in IL(aq) activities in equivalent conditions and at least 35-fold larger than sample-to sample variability. A large degree of variability in IL(aq) lixiviant activity is presented at nominal [HSO4](aq) and acidity for closely structurally-related ILs. Best performing [CnCmim][HSO4](aq) and [NR4∙HSO4(aq)](aq) IL(aq) systems are presented, alongside the confirmation of a non-trivial [IL](aq) dependence, which is a contrasting result to previous work with Cu flotation concentrates. Several ILs have been found to provide significant leaching at low acidity, ‘additive-quantity’ [IL](aq). Best performing IL(aq) systems have been scrutinised in an up-scaled tank leaching configuration for ~1 month leach durations. 450 mmol∙dm-3 NH4∙HSO4(aq) is demonstrated to enhance CuFeS2(s) dissolution compared with equivalent acidity H2SO4 under otherwise equal conditions. A combination of surface, bulk and solution speciation studies are untaken to obtain a global view of the IL(aq)-CuFeS2(s) dissolution process, with continuous in situ monitoring of key physical conditions ([Mn+](aq), [H+](aq), T, Eh). The role of surface oxygen and sulfur in CuFeS2(s) dissolution hindrance is examined. Experimental insights provided by consideration of the effect of SO42-(aq) and base addition to the primitive IL(aq) lixiviant media has led to the proposal of a HSO4-IL dissolution mechanism for CuFeS2(s).
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House, Charles Iain. "The electrogeneration of Cr(II) and V(II) solutions and the hydrometallurgical reduction of SnO2, PbS and CuFeS2." Thesis, Imperial College London, 1986. http://hdl.handle.net/10044/1/38039.
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Oliveira, Lucas Agostinho de. "Fotoeletrodos de CuFeO2 : eletrossíntese e caracterização." Universidade Estadual de Londrina. Centro de Ciências Exatas. Programa de Pós-Graduação em Química, 2014. http://www.bibliotecadigital.uel.br/document/?code=vtls000190556.
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Devido às preocupações ambientais nas últimas décadas novas fontes de energia sustentáveis estão sendo, cada vez mais, levadas em consideração para o uso na sociedade atual. Neste sentido, o hidrogênio produzido a partir da radiação solar pode ser considerado uma energia alternativa. Portanto existe um grande interesse na síntese e identificação a baixo custo/benefício de semicondutores do tipo p baseados em óxidos ativos na faixa do visível. Neste contexto, a síntese de filmes finos de CuFeO2 foi realizada por eletroprecipitação potenciostática e pulsada via redução de nitrato e de CuFeO2 na forma de pó nanoestruturado pelo método de síntese de combustão em solução (SCS) utilizando como combustíveis separadamente ácido cítrico, alanina, glicina e uréia na presença e na ausência do surfatante Tween 80® e sua caracterização física e fotocatalítica. As eletroprecipitações pulsada e potenciostática apresentaram-se eficazes para a síntese eletroquímica de filmes finos de CuFeO2. Os melhores potenciais para eletroprecipitação de Cu e Fe foram -0,1 V e -0,9 V, respectivamente, e a melhor razão molar Cu/Fe na solução precursora foi de 1:1. O filme obtido por eletroprecipitação pulsada apresentou-se mais cristalino e homogêneo que o filme obtido por eletroprecipitação a potencial fixo, no entanto, os filmes apresentaram fases de CuFeO2, CuFe2O4 e CuO. Os filmes apresentaram transição direta entre as BV e BC, com Ebg correspondente à CuFeO2 de 1,70 eV e 1,52 eV para os filmes eletroprecipitados a potencial fixo e pulsado, respectivamente. O filme obtido por eletroprecipitação pulsada apresentou fotocorrente de 36 μA e o filme eletroprecipitado a potencial fixo de 9 μA. Os potenciais eletroquímicos das BV e BC são de -0,3 e 1,4 para o filme eletrodepositado a potencial fixo, respectivamente, e de -0,27 e 1,25 para o filme eletrodepositado a potencial pulsado. As amostras obtidas por SCS apresentaram em suas composições CuFeO2, CuFe2O4, CuO e Fe2O3. Ambas as amostras sintetizadas por SCS com razão molar de combustível/metais de 1:1 e 2:1 e a amostra obtida por síntese em estado sólido calcinadas a 600°C apresentaram a mesma atividade fotocatalítica, enquanto a amostra sintetizada por SCS calcinada a 1000°C apresentou atividade fotocatalítica aproximadamente 50 % maior que as outras. A presença de Tween 80® aumentou a atividade fotocatalítica das amostras sem o surfatante, tendência apresentada também pelos difratogramas. A amostra obtida pela alanina na presença do surfatante apresentou a maior atividade fotocatalítica, enquanto a amostra sintetizada apenas com a alanina apresentou a menor atividade fotocatalítica entre todos os combustíveis utilizados.Due to environmental concerns in recent decades new sustainable energy sources are being increasingly taken into consideration for use in today's society. Accordingly, the hydrogen produced from solar radiation can be considered an alternative energy. There is great interest in the synthesis and identification at low cost/benefit of p-type semiconductor oxides-based assets in the visible range. In this context, the synthesis of thin films CuFeO2 was performed by potentiostatic electroprecipitation and pulsed electroprecipitation route nitrate reduction and CuFeO2 in the form of nanostructured powders by combustion synthesis in solution method (CSS ) using as fuel separately citric acid, alanine, glycine and urea in the presence and absence of the surfactant Tween 80®, and their physical and photocatalytic characterization. The pulsed and potentiostatic electroprecipitation showed to be effective for the electrochemical synthesis of thin films of CuFeO2 route nitrate reduction. The most suitable potential for electroprecipitation of Cu and Fe were -0.1 V and -0.9 V, respectively , and the best Cu/Fe mole ratio in the precursor solution was 1:1. The film obtained by pulsed electroprecipitation found to be more crystalline and homogeneous film obtained by the fixed potential, however, the films exhibited phases CuFeO2, CuFe2O4 and CuO. The films showed direct transition between BV and BC, with the corresponding Ebg to CuFeO2 1.70 eV and 1.52 eV for the films obtained by fixed and pulsed potential, respectively. The film obtained by pulsed electroprecipitation had photocurrent (36 μA ) 4 times higher than the obtained fixed potential film (9 μA ) . The electrochemical potential of BV and BC are 0,41 and -1,29 for the film electrodeposited at a fixed potential, respectively, and 0,41 and -1,16 for the pulsed potential electrodeposited film. The samples obtained by CSS presented in their compositions CuFeO2, CuFe2O4, CuO and Fe2O3. Both samples synthesized by CSS with a fuel/metal molar ratio of the of 1:1 and 2:1 ratios and the sample obtained by solid state synthesis calcined at 600 ° C showed almost the same photocatalytic activity while the sample synthesized by CSS with fuel/metal molar ratio of 1:1 calcined at 1000 ° C showed photocatalytic activity about 50 % higher than the other. The presence of Tween 80® increased the photocatalytic activity of the samples without surfactant, a trend also shown by XRD patterns . The sample obtained by alanine in the presence of surfactant showed the highest photocatalytic activity, whereas the sample synthesized only with alanine had the lowest photocatalytic activity among all fuels.
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Forslund, Axel. "Synthesis and characterisation of delafossite CuFeO2 for solar energy applications." Thesis, Uppsala universitet, Fasta tillståndets fysik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-297710.
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Delafossite CuFeO2 is an intrinsic p-type semiconductor with a band gap around 1.5 eV. Further, it is composed of relatively abundant, nontoxic elements, and therefor have potential to be an attractive material for solar energy harvesting.This work examines three routes to synthesise this material. The first includes a sol-gel deposition and then relies on solid state reaction above 650 degrees Celsius in inert gas atmosphere. In this work, no delafossite is obtained with this method.The second method is a hydrothermal route to make particles under hydrostatic pressure in an autoclave. Delafossite is obtained mixed with other phases.The third route includes aqueous precipitation similar to the second route, but a temperature of 70 degrees Celsius and ambient pressure is sufficient to produce a pure delafossite particle phase. It provides a robust and simple way to make delafossite CuFeO2 particles.The resulting particles are deposited and compressed on glass into thin films.The films have a band gap slightly below 1.5 eV and show some photoactivity in electrochemical measurements.
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Hermans, Yannick. "Interface analysis and development of BiVO4 and CuFeO2 heterostructures for photochemical water splitting." Phd thesis, Bordeaux, 2019. http://tuprints.ulb.tu-darmstadt.de/8700/1/Complete_thesis%20-%20German.pdf.
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Solar photo(electro)chemical (PEC) water splitting is regarded as a promising ways of renewable hydrogen production. Especially, type 2 PEC systems, in which the necessary energy needed to split water can be supplied by two complimentary photoabsorbers, have the potential to economically compete with steam methane reforming, the conventional hydrogen production method. In this work, BiVO4 and CuFeO2 were chosen to perform the water oxidation and water reduction reaction, respectively. However, according to literature additional contact materials are required to achieve a reasonable water splitting performance.
The exact benefits of these contact materials have not yet been completely elucidated. Therefore, we opted in this work to investigate the junction properties of certain BiVO4 and CuFeO2 based heterostructures through so called interface experiments, whereby a certain contact material was stepwise sputtered onto a BiVO4 or CuFeO2 substrate, performing photoelectron spectroscopy measurements in between each deposition step. In this way we could interpret the band
alignment between the substrate and the contact material, as well as determine the Fermi level tunability for the studied photoabsorbers.
In parallel, new anisotropic CuFeO2 and BiVO4 based heterostructured powders were created through photodeposition. In particular, silver, platinum, cobalt(oxy)(hydr)oxide and nickel(oxy)(hydr)oxide were successfully deposited onto anisotropically shaped BiVO4 and CuFeO2 powders. These powders were tested as well for their performance in photochemical water splitting.
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Sono, Sandisiwe. "Comparing estimates of zooplankton abundance from CUFES samples with those from a vertical bongo net." Master's thesis, University of Cape Town, 2008. http://hdl.handle.net/11427/6456.
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Includes bibliographical references (leaves 27-32).The accuracy of using CUFES (continuous underway fish egg sampler) as an alternative method to vertical bongo nets for sampling zooplankton abundance and distribution is assessed. Analysis is based on 14 taxonomic groups representing a wide variety of organism sizes. Samples were collected in March 2004 in the southern Benguela, South Africa. In total, 64 CUFES samples were collected while the ship was underway and 32 CUFES and vertical bongo net on-station samples were collected along four inshore-offshore transects. The frequencies of obtaining the taxa using the CUFES and vertical bongo net samples were the same for small copepods, amphipod adults and juveniles, and Nannocalanus.
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Hermans, Yannick [Verfasser], Wolfram [Akademischer Betreuer] Jaegermann, and Thierry [Akademischer Betreuer] Toupance. "Interface analysis and development of BiVO4 and CuFeO2 heterostructures for photochemical water splitting / Yannick Hermans ; Wolfram Jaegermann, Thierry Toupance." Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2019. http://d-nb.info/1188817647/34.
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Lusa, Makeli Garibotti. "Caracterização morfoanatômica e histoquímica de Cuphea Carthagenensis (Jacq.) J.F. Macbr.(Lytraceace) e avaliação em ambientes hidrofítico e mesofítico." reponame:Repositório Institucional da UFPR, 2010. http://hdl.handle.net/1884/23385.
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Schuldt, Elke Zuleika. "Avaliação farmacológica do extrato bruto hidroalcóolico, frações e composto isolado de Cuphea carthagenensis Jacq McBrite (sete-sangrias) determinação da capacidade de antioxidante /." Florianópolis, SC, 1999. http://repositorio.ufsc.br/xmlui/handle/123456789/81043.
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Dissertação (Mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Biológicas.Made available in DSpace on 2012-10-18T22:16:01Z (GMT). No. of bitstreams: 0Bitstream added on 2016-01-09T01:58:00Z : No. of bitstreams: 1 147104.pdf: 3557687 bytes, checksum: f8fe92b9263ee58f8393b5fffd5ec154 (MD5)
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Lalanne, Maëva. "Étude de phases delafossite CuFe1-xCrxO2 : vers de nouveaux TCO de type p." Toulouse 3, 2010. http://thesesups.ups-tlse.fr/1257/.
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Ces travaux ont pour objectif d'élaborer sous forme de couches minces des phases delafossite CuFe1-xCrxO2:Mg par pulvérisation cathodique radiofréquence, en vue de leur utilisation potentielle en tant que conducteurs transparents. Différentes poudres de composition CuFe1-xCrxO2 (0 = x = 1) ont été élaborées par réaction à l'état solide. Ces oxydes cristallisent avec la structure delafossite et une solution solide complète a été obtenue. L'étude thermostructurale de ces composés nous a permis de définir leur domaine de stabilité sous atmosphère oxydante et réductrice. Des caractérisations physico-chimiques ont également été effectuées sur ces matériaux. Nous avons ainsi montré que le domaine de stabilité des phases CuFe1-xCrxO2 augmente avec la quantité de chrome et que les composés riches en chrome sont les plus conducteurs et les moins absorbants. Au vue de ces résultats, des films minces de delafossite de composition CuFeO2:Mg et CuCrO2:Mg ont été obtenus par pulvérisation cathodique RF à température ambiante à partir des cibles céramiques. Après recuit sous vide à 450°C, les propriétés optoélectroniques des dépôts de CuFeO2:Mg se sont avérées limitées pour une utilisation en tant que TCO de type p dans le domaine du visible ; toutefois ces composés restent prometteurs pour des applications dans l'infra-rouge ou comme matériaux absorbeurs dans le visible. Les couches minces de CuCrO2:Mg présentent, après recuit sous vide à 450°C, une conductivité de type p de l'ordre de 0,1 S. Cm-1 et un gap optique de 3,13 eV. Ces valeurs peuvent être augmentées par des recuits à des températures supérieures à 450°CThis work concerns the development of CuFe1-xCrxO2:Mg delafossite oxide thin films deposited by RF-magnetron sputtering for the potential transparent conductor applications. Various CuFe1-xCrxO2 (0 = x = 1) powders were synthesized by a standard solid-state reaction. These oxides crystallize with the delafossite structure and a complete solid solution was obtained. Thermo-structural study has revealed the stability range of CuFe1-xCrxO2 compounds under oxidizing and reducing atmosphere. Their physical properties were also characterized. Thus, we showed that the stability range increases with the chromium quantity and chromium-rich delafossites are the most conductive and the least absorbent. Then, CuFeO2:Mg and CuCrO2:Mg delafossite thin films were prepared at room temperature by RF-magnetron sputtering from ceramic targets. After annealing under vacuum at 450°C, CuFeO2:Mg thin films have too low optoelectronic properties for p-type TCO application in the visible range; however these compounds are promising for infra-red TCO applications and/or absorber for photovoltaic application. After annealing under vacuum at 450°C, the p-type conductivity and the bandgap of CuCrO2:Mg thin films are about 0,1 S. Cm-1 and 3,13 eV respectively. These values can be increased by annealing at higher temperature than 450°C
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Mugnier, Emmanuelle. "Elaboration et caractérisation de couches minces du système Cu-Fe-O : des nanocomposites Cu/CuxFe3-xO4 à la delafossite CuFeO2 : vers l'élaboration de conducteurs tranparents de type p." Toulouse 3, 2007. http://www.theses.fr/2007TOU30012.
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Ces travaux de recherche avaient pour objectif l'élaboration de couches minces de delafossite CuFeO2 par pulvérisation cathodique radiofréquence à température ambiante dans l'optique ultérieure d'applications TCO. Dans une première partie, nous avons optimisé le procédé d'élaboration de disques de CuFeO2 en vue de l'élaboration d'une cible de pulvérisation. Par ailleurs, nous avons étudié la stabilité de ce composé sous atmosphère oxydante. Cette étude a montré la possibilité d'oxyder partiellement CuFeO2 en CuFeO2+d avec d = 0,18. Dans une seconde partie, nous avons corrélé les paramètres de dépôt avec la structure des couches minces. Lors de l'élaboration de nanocomposites Cu/CuxFe3-xO4, un phénomène d'auto-organisation des particules métalliques de surface a été mis en évidence. Enfin, nous avons synthétisé des couches minces de CuFeO2 qui présentent une conductivité de type p, une résistivité d'environ 103W. Cm et une transmission maximale dans le domaine du visible de 55%The aim of my research work was to elaborate delafossite CuFeO2 thin films by rf-sputtering at room temperature for future TCO applications. Firstly, we optimised the CuFeO2 ceramic elaboration process, which have then been transposed to the elaboration of the sputtering target. In addition, we studied its stability under air atmosphere. We thus showed that the partial oxidation of CuFeO2 to CuFeO2+d is possible with d = 0,18. In a second part, we correlated sputtering parameters with thin films composition, mainly by relating the energetical phenomena generated by these parameters with oxido-reduction phenomena. We thus reached different part of the Cu-Fe-O phase diagram. When elaborating nanocomposites Cu/CuxFe3-xO4, a self-assembly phenomenon of surface metallic particles has been observed. Finally, we synthesized delafossite thin films, which have a p-type conductivity, a resistivity of about 103W. Cm and a maximal transmission in the visible spectra of 55% for a 100nm thick film
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Mayor, Elizabeth Laura. "Fabrication and Characterization of Electrospun Poly-Caprolactone-Gelatin Composite Cuffs for Tissue Engineered Blood Vessels." Digital WPI, 2015. https://digitalcommons.wpi.edu/etd-theses/512.
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Strong, durable terminal regions that can be easily handled by researchers and surgeons are a key factor in the successful fabrication of tissue engineered blood vessels (TEBV). The goal of this study was to fabricate and characterize electrospun cuffs made of poly-caprolactone (PCL) combined with gelatin that reinforce and strengthen each end of cell-derived vascular tissue tubes. PCL is ideal for vascular tissue engineering applications due to its mechanical properties; however, PCL alone does not support cell attachment. Therefore, we introduced gelatin, a natural matrix-derived protein, into the electrospun material to promote cell adhesion. This work compared the effects of two different methods for introducing gelatin into the PCL materials: gelatin coating and gelatin co-electrospinning. Porosity, pore size, fiber diameter, and mechanical properties of the electrospun materials were measured in order to compare the features of gelatin PCL composites that have the greatest impact on cellular infiltration. Porosity was quantified by liquid intrusion, fiber diameter and pore size were measured using scanning electron microscopy, and tensile mechanical testing was used to evaluate strength, elastic modulus, and extensibility. Attachment and outgrowth of smooth muscle cells onto cuff materials was measured to evaluate differences in cellular interactions between materials by using a metabolic attachment assay and a cellular outgrowth assay. Finally, cuffs were fused with totally cell-derived TEBV and the integration of cuffs with tissue was evaluated by longitudinal pull to failure testing and histological analysis. Overall, these cuffs were shown to be able to add length and increase strength to the ends of TEBV for tube cannulation and manipulation during in vitro culture. In particular, PCL:gelatin cospun cuffs were shown to improve cellular attachment and cuff fusion compared to pure PCL cuffs, while still increasing the strength of the TEBV terminal ends.
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Ryan, Patrick. "REDUCING EFFLUENT PHOSPHORUS AND NITROGEN CONCENTRATIONS FROM A STORMWATER DETENTION POND USING A CHAMBER UPFLOW FILTER AND SKIM." Master's thesis, University of Central Florida, 2008. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4307.
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Stormwater runoff is a known pollutant source capable of causing surface water degradation, especially in highly populated areas such as Central Florida. Wet detention ponds manage this stormwater, but most of the ponds do not remove enough nutrients, specifically nitrogen and phosphorus, to meet TMDL regulations. This research provides a possible addition to a detention pond in Seminole County, Florida using a Chamber Upflow Filter and Skimmer (CUFS), which can increase the removal of phosphorus and nitrogen by the system. Water enters the system through the skimmer, which floats on the surface of the detention pond. It travels from the skimmer to the bottom of the chamber, where heavier particles settle out before entering the upflow filter. The upflow filter contains twenty-four inches of Black and GoldTM media to remove nitrogen and phosphorus under anoxic conditions. Water flows up through the filter and out of the system, and eventually travels to Lake Jesup, a eutrophic lake. A total of twenty-eight storm events and seven baseflows were sampled from the site in Seminole County, and ten storm events were sampled from a pilot study CUFS. The results of this research show significant reductions by the Seminole County CUFS in turbidity, orthophosphorus, total phosphorus, and total suspended solids when the means were compared at a 95% confidence interval. Reductions also occurred for total nitrogen, but could not be proved by the mean comparison. The pilot scale application of the CUFS significantly reduced total nitrogen at a 95% confidence interval.M.S.Env.E.
Department of Civil and Environmental Engineering
Engineering and Computer Science
Environmental Engr MSEnvE
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Crouch, David Alexander. "Morphometric analysis of neural tissue following long-term implantation of nerve cuffs in the cat forelimb." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/mq24113.pdf.
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Rivas, Mendoza Angel E. "Ondas de densidad de espin en el compuesto casi-2D CuFeTe2 : evidencia directa de la coexistencia de los estados normal y condensado." Toulouse 3, 2005. http://www.theses.fr/2005TOU30010.
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Dans ce travail de thèse nous avons réalisé une étude rigoureuse, au moyen de différentes techniques expérimentales, du comportement magnétique et électrique du composé laminaire CuFeTe2. Cinq échantillons ont été analysés, quatre ayant été préparés par la méthode standard de fusion et recuit et l'un d'eux par la méthode de croissance verticale de Bridgman. Une étude de la composition chimique au moyen de la technique EDX montre que l'un des échantillons est stoechiométrique. Les résultats de diffraction de rayons X confirment la structure tétragonale et laminaire du composé. Les résultats des mesures de susceptibilités magnétiques, faites dans une balance de Faraday (78-350 K, sous un champ de 2. 8 kG) et dans un magnétomètre SQUID (2-320 K, sous des champs de 35 et 70 Gauss), indiquent l'apparition d'un ordre antiferromagnétique au dessous d'environ 300 K, avec un comportement paramagnétique de Pauli au dessus de cette température. Le comportement est attribué à la formation d'un état d'Ondes de Densité de Spin (ODS) dans le CuFeTe2. Un autre élément en faveur de l'existence de l'ODS est donné par les mesures d'effet Mössbauer: Dans le domaine de température 2-310 K il apparaît une variété de spectres qui vont d'une structure magnétique incommensurable, en passant par une superposition de l'état magnétique avec une contribution non magnétique, jusqu'à la disparition complète du premier. Pour confirmer le caractère itinérant du magnétisme observé, un spectre réalisé sous un champ de 6. 5 Tesla montre que le fer n'a pas de moment magnétique localisé. ,Ces résultats nous ont permis de donner une nouvelle interprétation de spectres Mösbauer observés en ODS, car on peut voir comment les proportions de l'état condensé (spectre de l'onde incommensurable) et de l'état normal (doublet paramagnétique) varient en fonction de la température. .In this thesis work we achieved a rigorous study, by means of different experimental techniques, of the magnetic and electric behavior of the layered compound CuFeTe2. Five samples have been analyzed: four have been prepared by standard melt and anneal techniques and one of them by the Bridgman vertical growth technique. A study of the chemical composition by the EDX technique shows that one of the samples is stoichiometric. The results of X-ray diffraction confirm the tetragonal layered structure of the compound. The magnetic measurements results, performed in a Faraday balance (78-350 K, under a magnetic field of 0. 28 T) and in a SQUID magnetometer (2-320 K, under fields of 35 and 70 G), indicate the appearance of an antiferromagnetic order below about 300 K, with a Pauli paramagnetic behavior above this temperature. This behavior is attributed to the formation of a Spin Density Wave (SDW) state in CuFeTe2. Another element in favor of the existence of the SDW is given by the Mössbauer effect measurements: In the temperature range 2-310 K a variety of spectra are observed, going from an incommensurate magnetic structure, to whom is superposed a non magnetic contribution as temperature raises, until the complete disappearance of the first one. To confirm the itinerant character of the observed magnetism, a spectrum recorded under a magnetic field of 6. 5 T shows that iron doesn't hold a magnetic moment. .
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Ioannoni, Raphaël. "Élucidation du rôle et du mécanisme d’action de la protéine Cuf2 lors de la méiose chez la levure Schizosaccharomyces pombe." Thèse, Université de Sherbrooke, 2016. http://hdl.handle.net/11143/9542.
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Chez Schizosaccharomyces pombe, le cycle méiotique est le mode de division cellulaire spécialisé qui permet la formation d’ascospores résistantes à différents stress lorsque les conditions environnementales ne sont pas propices à la multiplication cellulaire. Lors de mes travaux de thèse, mes objectifs consistaient à caractériser le rôle et le mécanisme d’action de la protéine Cuf2 lors du cycle méiotique chez S. pombe. Mes résultats ont montré que le gène cuf2[indice supérieur +] était exprimé exclusivement lors des divisions méiotiques et que la protéine se co-localisait de manière constitutive avec le matériel génétique. De plus, mes résultats ont dévoilé que Cuf2 participait à l’activation et à la répression de plusieurs gènes méiotiques selon un mécanisme de nature transcriptionnelle en s’associant spécifiquement avec leur région promotrice. Par la suite, mes résultats ont mis en évidence que Cuf2 interagissait physiquement avec Mei4, un facteur de transcription méiose-spécifique, au noyau des cellules méiotiques. Notamment, mes résultats ont montré que la présence de Mei4 et de son motif de liaison à l’ADN dénommé FLEX étaient nécessaires afin que Cuf2 puisse s’associer au promoteur de son gène cible fzr1[indice supérieur +] afin d’en activer l’expression. L’ensemble de mes résultats indiquent que Cuf2 et Mei4 interagissent aux promoteurs de certains gènes lors des divisions méiotiques afin d’en co-activer l’expression. D’ailleurs, mes résultats ont également montré que la fonction de Cuf2 était importante à la formation d’ascospores et à leur viabilité ; en absence de Cuf2, la majorité des ascospores présentent diverses aberrations et plus de la moitié d’entre elles sont non-viables. Globalement, mes résultats démontrent que Cuf2 est un régulateur critique de l’expression génique lors du cycle méiotique et que cette fonction est essentielle à la sporulation chez S. pombe.
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Fugate, Elizabeth Anne. "Understanding the Role of Lattice Defects and Metal Composition Ratio on the Photochemistry of CuFeO2 toward Solar Energy Conversion." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu157788103637799.
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Jimmy, Adamo, and Abdi Hamse. "Behavior of polygonal semi-closed thin-walled cross-section : A study based on finite strip analysis." Thesis, Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-62257.
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The acceptance and the use of cold-formed steel sections has significantly increased in recent years due to advantages such as consistency and accuracy of profile, ease of fabrication, high strength and stiffness to the lightness in the weight. For thin-walled columns, made by folding a plane plate into a section, it is possible that when they are subjected to compression loads they may buckle either locally, if the member is very short, or globally if the member is very long. In addition to local and global buckling, a thin-walled member of an open cross section may also show buckling involving a “distortion” of the cross section. Compared to local and global buckling, distortional buckling is not very familiar and has been discovered only in thin-walled members of open cross sections such as cold-formed steel section columns. The objective of this study is to investigate the behavior of polygonal semi-closed cross-section with pure compression. The study comprise to only elastic buckling and the methodology is consisted by using CUFSM analysis. In order to execute CUFSM of polygonal profiles, the scripts have created which match the Matlab script files (m-files) downloaded from CUFSM 4 open source. The distortional buckling mode is governing as a buckling failure, which occur and dominate in the cases where spring values are 100 kN or higher. However, the contrary result reveals by a decreasing of the spring values. The behavior of the cross-section is dependent on how the interaction of different buckling modes prevails at the corresponding critical half-wavelength. Considering the predomination of distortional buckling mode indicates that the most of polygonal cross-section do not behave as rigid, i.e. as whole cross-section. A reducing of distortional mode and increasing of local mode as well as global mode gives indication that the behavior of the cross-section has changed and turned significantly into more rigid and thus is expected to behave more as whole cross-section. The more spring values decrease, the higher global mode arises and dominates for the lower slenderness range. The critical half-wavelength for each profile illustrates the needed density between bolts on the longitudinal part of the member. In the interest of eliminating distortional buckling failure, due the fact that distortional buckling is unpredictable, the bolt-density should be lower than the corresponding half-wavelength for the profile where the distortional mode is predominating.
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Blauth, Pricila Lidiane [UNESP]. "Oxidação da calcopirita (CuFe S'IND.2') por Acidithiobacillus ferooxidans em presença de cisteína e de Acidithiobacillus thiooxidans." Universidade Estadual Paulista (UNESP), 2008. http://hdl.handle.net/11449/88046.
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O processo de biolixiviação é a utilização de bactérias, para a solubilização dos metais presentes em sulfetos minerais. As espécies mais estudadas são o Acidithiobacillus thiooxidans e o Acidithiobacillus ferrooxidans, embora outras espécies também participem do processo. Esse processo é aplicado há muito tempo, mas somente nos anos 1950 a participação de microorganismos foi descoberta. A biolixiviação de cobre é um exemplo de aplicação industrial, embora outros metais como ouro, urânio e o níquel, venham sendo obtidos por esse método. A calcopirita (CuFeS2) é o mais abundante mineral de cobre e também o mais refratário ao ataque químico ou bacteriano. Dessa forma, existe um grande interesse no desenvolvimento de alternativas para otimizar a solubilização desse sulfeto. Neste trabalho investigou-se a avaliação do efeito do aminoácido cisteína na biolixiviação de uma amostra de calcopirita utilizando linhagens de A. ferrooxidans e A. thiooxidans. Inicialmente foram realizados testes de respirometria celular com A. ferrooxidans e sulfato ferroso como substrato em diferentes concentrações de cisteína (0, 10-1, 10-3, 10-5, 10-7 mol L-1) para avaliar o efeito inibitório da cisteína na atividade da bactéria. Somente 10-1 mol L-1 provocou uma inibição significativa na oxidação do íon ferroso pela bactéria. A seguir foram realizados ensaios utilizando a calcopirita como substrato, na presença das mesmas concentrações de cisteína. A cisteína em 10-1 mmol L-1 também determinou inibição significativa na oxidação do mineral. As demais concentrações provocaram um aumento na velocidade inicial de oxidação do sulfeto em comparação com o controle na ausência de cisteína. Em ensaios de crescimento da bactéria na presença de meio contendo o íon ferroso, foram obtidos resultados semelhantes aos anteriores, destacando-se...
Bioleaching is the solubilization and recovery of metals from sulfides minerals promoted by bacterial metabolism. Although Acidithiobacillus thiooxidans and Acidithiobacillus ferrooxidans are the most studied bacteria, other species contribute to that process. Despite the bioleaching has been utilized for long time, only in the 1950´s the active participation of bacteria was demonstrated. Copper bioleaching is the classical industrial application example, although gold, uranium and nickel have been produced by that technique. Chalcopyrite (CuFeS2) is the most abundant copper mineral the most refractory as such. Thus, there is an enormous interest in developing alternatives to optimize this sulfide solubilization. The effect of cysteine on the chalcopyrite dissolution in the presence of A. ferrooxidans and A. thiooxidans was evaluated in this study. Respirometric assays were used initially to test the effects of cysteine in the ferrous or chalcopyrite oxidation by A. ferrooxidans at pH 1.8 in the following amino acid concentrations: 0, 10-1, 10-3, 10-5, 10-7 mol L-1. In both cases, only 10-1 mol L-1 of cysteine was inhibitory to the bacterial oxidation and in the other concentrations a slight increase in the initial oxidation rate was observed, comparing to the control in absence of this amino acid. In growth experiments utilizing ferrous ion as substrate and in the same concentrations of cysteine, 10-3 and 10-5 mol L-1 established an increase in the rate of bacterial growth. These cysteine concentrations were selected to run bioleaching tests through shaking flasks technique. Previously, A. ferrooxidans was acclimated to growth in medium containing only chalcopyrite as substrate, by progressive ferrous iron substitution as energy source. Acclimated A. ferrooxidans cells were utilized in shaking flasks experiments in several conditions such as, inoculation or not... (Complete abstract click electronic access below
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Blauth, Pricila Lidiane. "Oxidação da calcopirita (CuFe S'IND.2') por Acidithiobacillus ferooxidans em presença de cisteína e de Acidithiobacillus thiooxidans /." Araraquara : [s.n.], 2008. http://hdl.handle.net/11449/88046.
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Resumo: O processo de biolixiviação é a utilização de bactérias, para a solubilização dos metais presentes em sulfetos minerais. As espécies mais estudadas são o Acidithiobacillus thiooxidans e o Acidithiobacillus ferrooxidans, embora outras espécies também participem do processo. Esse processo é aplicado há muito tempo, mas somente nos anos 1950 a participação de microorganismos foi descoberta. A biolixiviação de cobre é um exemplo de aplicação industrial, embora outros metais como ouro, urânio e o níquel, venham sendo obtidos por esse método. A calcopirita (CuFeS2) é o mais abundante mineral de cobre e também o mais refratário ao ataque químico ou bacteriano. Dessa forma, existe um grande interesse no desenvolvimento de alternativas para otimizar a solubilização desse sulfeto. Neste trabalho investigou-se a avaliação do efeito do aminoácido cisteína na biolixiviação de uma amostra de calcopirita utilizando linhagens de A. ferrooxidans e A. thiooxidans. Inicialmente foram realizados testes de respirometria celular com A. ferrooxidans e sulfato ferroso como substrato em diferentes concentrações de cisteína (0, 10-1, 10-3, 10-5, 10-7 mol L-1) para avaliar o efeito inibitório da cisteína na atividade da bactéria. Somente 10-1 mol L-1 provocou uma inibição significativa na oxidação do íon ferroso pela bactéria. A seguir foram realizados ensaios utilizando a calcopirita como substrato, na presença das mesmas concentrações de cisteína. A cisteína em 10-1 mmol L-1 também determinou inibição significativa na oxidação do mineral. As demais concentrações provocaram um aumento na velocidade inicial de oxidação do sulfeto em comparação com o controle na ausência de cisteína. Em ensaios de crescimento da bactéria na presença de meio contendo o íon ferroso, foram obtidos resultados semelhantes aos anteriores, destacando-se... (Resumo completo, clicar acesso eletrônico abaixo)Abstract: Bioleaching is the solubilization and recovery of metals from sulfides minerals promoted by bacterial metabolism. Although Acidithiobacillus thiooxidans and Acidithiobacillus ferrooxidans are the most studied bacteria, other species contribute to that process. Despite the bioleaching has been utilized for long time, only in the 1950's the active participation of bacteria was demonstrated. Copper bioleaching is the classical industrial application example, although gold, uranium and nickel have been produced by that technique. Chalcopyrite (CuFeS2) is the most abundant copper mineral the most refractory as such. Thus, there is an enormous interest in developing alternatives to optimize this sulfide solubilization. The effect of cysteine on the chalcopyrite dissolution in the presence of A. ferrooxidans and A. thiooxidans was evaluated in this study. Respirometric assays were used initially to test the effects of cysteine in the ferrous or chalcopyrite oxidation by A. ferrooxidans at pH 1.8 in the following amino acid concentrations: 0, 10-1, 10-3, 10-5, 10-7 mol L-1. In both cases, only 10-1 mol L-1 of cysteine was inhibitory to the bacterial oxidation and in the other concentrations a slight increase in the initial oxidation rate was observed, comparing to the control in absence of this amino acid. In growth experiments utilizing ferrous ion as substrate and in the same concentrations of cysteine, 10-3 and 10-5 mol L-1 established an increase in the rate of bacterial growth. These cysteine concentrations were selected to run bioleaching tests through shaking flasks technique. Previously, A. ferrooxidans was acclimated to growth in medium containing only chalcopyrite as substrate, by progressive ferrous iron substitution as energy source. Acclimated A. ferrooxidans cells were utilized in shaking flasks experiments in several conditions such as, inoculation or not... (Complete abstract click electronic access below
Orientador: Oswaldo Garcia Junior
Coorientador: Denise Bevilaqua
Banca: Wilson Cervi da Costa
Banca: Luis Gonzaga Santos Sobral
Mestre
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Lelièvre, Stéphanie. "Identification et caractérisation des frayères hivernales en Manche Orientale et la partie sud de la mer du Nord : Identification des oeufs de poissons, cartographie et modélisation des habitats de ponte." Nantes, 2010. http://www.theses.fr/2010NANT2110.
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Une meilleure connaissance des frayères des principaux poissons commerciaux de la mer du Nord semble nécessaire pour leur surveillance. La composition et l'abondance des espèces d'oeufs collectés par le CUFES (Continuous Underway Fish Egg Sampler) sont comparées à celle collectées par le VET (Vertical Egg Trawl) permettant de prouver l'efficacité du CUFES en Manche et mer du Nord. L'identification des œufs de poissons principalement basée sur des critères morphologiques n'est pas toujours fiable. En effet, certaines espèces comme la morue (Gadus morhua) et le merlan (Merlangius merlangus) ont la même gamme de taille, ainsi des méthodes altenatives ont été développées. Premièrement, une technique de biologie moléculaire par PCR-RFLP puis un nouveau système d'analyse d'images, le ZooScan ont été développés pour identifier les œufs de poissons. Des cartes annuelles des frayères hivernales ont été réalisées et comparées entre elles afin de déterminer des zones de ponte récurrentes. Les œufs sont généralement bien distribués sur la zone d'étude, à l'exception de la zone Nord-Ouest de la mer du Nord, près des côtes écossaises. Et enfin, l'habitat de ponte des poissons a été modélisé en utilisant les méthodes GLM (Generalised Linear Model) et RQ (Regression Quantile) en fonction des paramètres environnementaux disponibles afin de prédire les frayères. Les résultats de cette étude multidisciplinaire ont permis d'améliorer les connaissances sur les frayères hivernales en Manche Orientale et sud mer du Nord et ont été discutés dans une perspective de protection et de conservation de ces zonesA better knowledge and monitoring of principal commercial fish spawning grounds have become necessary in the North Sea. The efficiency of CUFES was proved by sampling pelagic fish eggs in winter in Eastern Channel and Southern North Sea. Fish egg taxonomic identification based on visual criteria cannot always be carried out effectively. In particular, cod (Gadus morhua), and whiting (Merlangius merlangus) or flounder (Platichthys flesus) and dab (Limanda limanda) have the same range of egg diameter and similar morphologies. Alternative identification methods using molecular techniques were developed to improve the accuracy of egg taxonomic identification. First, PCR-RFLP method, then, in order to accelerate egg identification, the use of a new laboratory imaging system, the ZooScan, able to produce high resolution images of zooplankton samples, was adapted to fish eggs and allower their automated identification using supervised learning algorithms. The location of winter spawning grounds of fishes in the Southern North Sea and the Eastern Channel was illustrated using yearly maps and analysed over the available period to define recurrent, occasional and unfavorable spawning areas. Generally, fish eggs were found over the study area, except for the North Western of the North Sea, near Scottish coasts. Important spawning areas were clearly localised along the Belgian, Dutch and Danish coasts. Habitat modelling of these fish spawning areas was carried out using both GLM (Generalised Linear Model) and QR (Regression Quantile) and associated egg abundance to physical conditions such as temperature, salinity, bedstress, chlorophyll a concentration and bottom sediment types to characterize spawning habitat conditions and predict their extent and location. The results of this approach improve the understanding of spawning grounds distribution and were discussed in the context of the protection and conservation of critical spawning grounds
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Cazottes, Sophie. "Microstructure à fine échelle d'alliages à propriétés de magnétorésistance géante: relation avec les propriétés magnétiques. Cas de rubans de Cu80FexNi20-x (x=5,10,15 at%)." Phd thesis, Université de Rouen, 2008. http://tel.archives-ouvertes.fr/tel-00330007.
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Un matériau magnétorésistif voit sa résistance électrique varier lorsqu'un champ magnétique lui est appliqué. Le but de cette étude est de relier les différents paramètres structuraux aux propriétés magnétiques et de magnétorésistance de systèmes granulaires de Cu80FexNi20-x (at%) élaborés sous forme de rubans. L'influence de la composition de l'alliage est d'abord présenté. Puis, la microstructure d'un ruban de Cu80Fe10Ni10(at%), présentant le maximum de magnétorésistance, a été précisément caractérisée de l'échelle microscopique à l'échelle atomique. Cet échantillon est constitué de précipités fcc riches en fer et en nickel cohérents avec la matrice riche en cuivre. L'étude des propriétés magnétiques de ce ruban a permis de montrer que des interactions magnétiques sont présentes qui diminuent la MRG. Les paramètres structuraux (distributions de taille et de composition, fraction volumique et densité de précipités, largeur des interfaces...) ont été corrélés aux propriétés magnétiques.
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Giagloglou, Kyriakos. "The identification and down selection of suitable cathode materials for use in next generation thermal batteries." Thesis, University of St Andrews, 2017. http://hdl.handle.net/10023/11563.
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In this work new novel cathode materials such as transition-metal sulfides, chlorides or fluorides were investigated and studied for their use in lithium ion thermal batteries. All cathodes were synthesized by a solid state reaction in sealed quartz tubes with a duration of firing for 1 week at high temperatures ( > 500 °C). All structures of compounds were probed by powder X-ray diffraction and the morphology and shape of crystallites of cathodes were characterized by scanning electron microscopy. The electrochemical properties of the batteries were investigated by galvanostatic discharge and galvanostatic intermittent titration technique at high temperatures (> 400 °C). All the batteries used as an anode Li₁₃Si₄, as an electrolyte LiCl-KCl eutectic and as separator MgO. All the products of the discharge mechanism were confirmed using powder X-ray diffraction and EDX analysis. CoNi₂S₄ and NiCo₂S₄ exhibit two voltage plateaux vs Li₁₃Si₄ at 500 °C, one at around 1.75 V and the second at 1.50 V. Capacities of 350 and 290 mA h g⁻¹ were achieved, respectively. NiS, Co₃S₄ and Co₉S₈ were confirmed as the products of discharge mechanism. ZrS₃ exhibits a single flat voltage plateau of 1.70 V at a current density of 11 mA/cm² and a capacity of 357 mA h g⁻¹, at 500 °C was obtained. A new material, LiZr₂S₄, was identified as the product of the electrochemical process, which can be indexed to a = 10.452(8) Å cubic unit cell. KNiCl₃ was tested at different current densities from 15 mA/cm² to 75 mA/cm² and a high cell voltage, with a capacity of 262 mA h g⁻¹ was achieved at 425 °C. Ni metal, KCl and LiCl were confirmed as the products of the discharge mechanism. Li₂MnCl₄ was tested at the same current densities as KNiCl₃ at 400 °C and a capacity of 254 mA h g⁻¹ was achieved. Mn metal and LiCl were confirmed as the products after discharge. Li₆VCl₈ has a capacity of 145 mA h g⁻¹ and a flat voltage plateau of 1.80 V at 500 °C. NiCl₂ has also a capacity of 360 mA h g⁻¹ and a high voltage profile of 2.25 V at 500 °C. CoCl₂ exhibits a lower capacity of 332 mA h g⁻¹ and lower voltage profile compared to NiCl₂ at 500 °C. CuF₂ and PbF₂ were tested at 500 °C. PbF₂ exhibits a single flat voltage plateau of 1.25 V and a capacity of 260 mA h g⁻¹ was obtained. CuF₂ has a high voltage profile but a voltage plateau could not be obtained.
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Greaves, Danielle Kathleen. "Désadaptations cardiovasculaires à la microgravité : techniques avancées pour améliorer la mesure et l'évaluation du risque cardiovaculaire induit par les vols spatiaux pour les équipages de longue durée Effects of exercise countermeasure on myocardial contractility measured by 4D speckle tracking during a 21-day head-down bed rest Cardiac and arterial structure and functional changes after four days of dry immersion with and without thigh cuffs Effect of thigh cuff on venous flow redistribution during 4 days in dry immersion." Thesis, Normandie, 2019. http://www.theses.fr/2019NORMC433.
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L'objectif était de quantifier les modifications de la contractilité cardiaque au cours d’un bedrest de 21 jours (HDBR) par la methode speckle tracking 4D et de déterminer si la contre-mesure « exercice » était capable de préserver cette contractilité cardiaque. Les méthodes traditionnelles 2D ne mesurent qu'une variation de la taille du ventricule de la systole à la diastole et ne suivent pas la cinetique des mouvements de contractilité à l’interieur de la paroi. De plus l’echographie 2D ne permet d’acceder qu’a la contractilite longitudinale globale par la mesure de la distance Apex-Valve mitrale. Le suivi des mouvements des speckles (points singuliers a l’interieur du myocarde) en 4D montre que la contractilité radiale diminuée signifcativement pendant le HDTBR chez les sujets témoins alors qu’elle est conservée dans le groupe exercice. Par contre la contractilité longitudinale n’est pas affectée dans aucun des 2 groupes. Bien sûr, l'IRM pourrait fournir des données similaires, mais il n’est pas possible à ce jour d’imaginer avoir une IRM a bord de l’ISS dans un futur proche. A la suite de ces resultats nous avons mis au point un algorithme de traitement des video cardiaque qui permet d’acceder a la contractilite radiale et longitudinale en vol (prog Vasc-Aging en cours) .L’objectif de l’experimentation était de montrer que quatre jours en immersion seche suffisaient pour realiser un transfert liquidien important vers les régions céphaliques comparable à celui observé en vol spatial. Notre protocole consistait donc a mesurer les volume veineux au niveau cervical cerebral et porte au debut de la periode en immersion (a 2h) puis a 4 jours d’immersion. Compte tenu des problemes engendrés par ce transfert liquidien en vol nous avions proposé de tester la capacité des brassarts de cuisse a reduire l’amplitude du transfert veineux. Les résultats montrent que l’immersion provoque un transfert de sang veineux au niveau cervical maximal à 2H et que les Brassarts de cuisse reduisent signifcativement ce transfert dans cette phase precoce. Par contre a 4 jours d’immersion l’amplitude du transfert sanguin est considerablement diminuée (bien que toujours presente) et les brassarts de cuisse n’ont pas d’effet visible à ce moment-là. En fait le volume plasmatique decroit significativement à la fin du premier jour (env 20%) des lors la masse de sang deplacées vers la tete par l’immersion est insuffisante pour generer une stase importante au niveau cervical comme à 2h d’immersion. Pour cette meme raison la vitesse dans les veines cerebrales n’est pas augmentée à 4 jours d’immersion contrairement à ce qu’on avait observé à 2h d’immersion lors d’une precedente etude. Donc le modele immersion seche est un modele pour etudier les transferts liquidiens en microgravité mais seulement en debut de phase d’immersion. Sur cette période de temps, les Brassarts de cuisse ont bien un effet protecteur pour les organes de la zone cephaliqueObjective: to evaluate functional myocardial contractility after 21 days of head-down bed rest (HDTBR) in sedentary control (CON) or with a resistive vibration exercise (RVE) countermeasure (CM) applied, by using 4D echocardiographic (4D Echo) imaging and speckle tracking strain quantification.Methods: Twelve volunteers were enrolled in a crossover HDTBR design, and 4D Echo was performed in supine position (REST) at BDC-2 and at R+2, and in -6° HDTBR (on day 18), and also during the first and the last minute of the 80° head-up step of Standard Measures tilt test, performed at both BDC-2 and R+2. Radial (Rad-Str), longitudinal (Lg-Str) and twist (Tw-Str) strain were measured by 4D speckle tracking, as well as left ventricle diastolic volume (LVDV) and mass (LVmass).Results: On day 18: in the CON group, LVDV and LVmass were reduced (p<0.05), the Rad-Str decreased (p<0.05) and Tw-Str showed a tendency to increase (p< 0.11), with no changes in Lg-Str. In RVE group, LVDV and LV mass, as well as all the strain parameters remained unchanged.On R+2: in the CON group, LVDV and LVmass were not recovered in all subjects compared to pre-HDTBR (p<0.08), Rad-Str was still decreased (p<0.05), while Tw-Str tended to increase (p<0.09). These parameters remained unchanged in the RVE group.Tilt 80°: Rad-Str and Lg-Str values at 80° tilt were similar post HDT in both groups.Conclusion: 4D Echo and speckle tracking analysis showed that in the CON group, Rad-Str decreased concomitant with LVmass and LVDV with HDTBR, but this observation did not support the hypothesis that this HDTBR induced remodelling or a muscle atrophy. RVE acted to preserve both LVmass, LVDV and contractility during HDTBR, thus proving its effectiveness to this aim. Nevertheless, the significant HDTBR-induced changes observed in the CON group had only a limited effect on the cardiac contractile response as observed during post HDTBR tilt test. The level of contractility at 80° Tilt position was not affected neither by HDTBR nor by RVE CM.Purpose: The objective was to quantify the venous redistribution during a 4-day dry immersion (DI) and evaluate the effect of thigh cuffs.Methods: The study included 9 control (Co) and 9 subjects wearing thigh cuffs during daytime hours (CU). Ultrasound images were collected Pre DI, on the fourth day in the morning (D4 AM) and on the fourth day in the afternoon (D4 PM), to assess the following outcome variables: left ventricle dimension, stroke volume, and ejection fraction (LVD, SV, EF), jugular vein volume (JV), portal vein dimension (PV), middle cerebral vein velocity (MCVv). An additional measure of JV dimension was performed on the first day after having worn the cuffs for two hours (D1 2H).Results: The JV volume increased significantly from Pre to D1 2H in both groups, but increased more in the Co compare to the CU subjects (Co: 0,27+/0.15cm3 to 0.94+/-0;22 cm3;P<0.01 CU: 0,32+/-0.13 cm3 to 0.64+/-0.32 cm3 P<0.042).At D4 AM no difference was found between the two treatment groups for any of the parameters listed above.Stroke volume and EF decreased from Pre (SV:111+/-23cm3 to 93+/-24 cm3 p<0.05; EF:0.66+/-0.07 to 0.62+/-0.07 p<0.05). JV volume was slightly, but significantly increased (Co: 0.47+/-0.22cm3 CU:0.35+/-014cm3 P<0.05), while MCVv and PV remained unchanged from Pre DI. From D4 AM to PM these parameters did not show any significant change.Conclusion: The results confirm that DI induces, during the first 2-3 h, a significant cephalic fluid shift as observed in spaceflight. During this early phase the thigh cuffs reduced the amplitude of the fluid shift towards the head, but after 4 days in DI there was only a slight memory (residual) effect of DI on the jugular volume and no residual effect of thigh cuffs
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Hsu, Kuo-Hwa, and 徐國華. "Structural Investigation of Cu-S and CuFeS2 Powders Prepared by Mechanochemical Synthesis." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/55003356432736388611.
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碩士逢甲大學
材料科學所
92
In the current study, we investigated the feasibility of synthesizing transition metal sulfides by mechanochemical reactions with a high energy SPEX 8000-D ball mixer. The structural evolutions of the long-range and short-range ordered structures during the process were examined using X-ray diffractometry (XRD) and synchrotron X-ray absorption spectroscopy (XAS), respectively. Experimental results revealed that mechanochemical reactions occurred during the milling process. For Cu-S and CuFeS2 systems, the concentration of sulfur influences the time for sulfide formation. For various compositions, CuS, Cu2S and CuFeS2 formed at the end of milling. SEM examination revealed that Cu-S and CuFeS2 systems follow a similar mechanism in forming sulfides. At the early stage of milling, the alloyed metals are fractured to embed fine S powders. After a period of milling, the refined powders are accompanied by an increase in internal strain, ultimately inducing the formation of sulfides. Moreover, extended X-ray absorption fine structure (EXAFS) and X-ray absorption near-edge structure (XANES) obtained from XAS were used to resolve the short range order and electronic properties of the milled alloys, respectively. EXAFS and XANES, along with XRD, provide a better understanding of the structural evolution caused by mechanochemical reactions of the transition metal sulfides during MA.
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Girma, Wubshet Mekonnen, and Wubshet Mekonnen Girma. "One-Pot Synthesis and Characterization of CuFeS2 Nanoparticles for Targeted Theranostic Biomedical Applications." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/5myn9s.
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博士國立臺灣科技大學
化學工程系
106
Nanoparticles with surface modified and conjugated with targeting groups are of central importance in biomedical applications. In this regard, I-III-VI semiconductor nanomaterials are a particular interest in multimodal imaging, biosensing, chemotherapy, photothermal therapy and photodynamic therapy as a whole in theranostic applications due to their fascinating properties when they interact with cancer cells. However, the synthesis process remains a problem in finding an approach to fabricate in large scale with monodispersed nanoparticles, related to a way of finding water-soluble nanoparticles and how to make them effective and efficient probe for diagnosis and therapeutic applications of cancer cells. In the present study, for the first time, CuFeS2 nanocrystals were successfully prepared through a facile noninjection-based synthetic strategy, by reacting Cu and Fe precursors with dodecanethiol in a 1-octadecene solvent. This one-pot noninjection strategy features easy handling, large-scale production, and high synthetic reproducibility. Following hyaluronic acid (HA) encapsulation, CuFeS2 nanocrystals coated with HA (CuFeS2@HA) not only readily dispersed in water and showed improved biocompatibility but also possessed a tumor-specific targeting ability of cancer cells bearing the cluster determinant 44 (CD44) receptors. The encapsulated CuFeS2@HA showed broad optical absorbance from the visible to the near-infrared (NIR) region and high photothermal conversion efficiencies of about 74.2%. They can, therefore, be utilized for the photothermal ablation of cancer cells with NIR light irradiation. In addition, toxicity studies in vitro (B16F1 and HeLa) and in vivo (zebrafish embryos), as well as in vitro blood compatibility studies, indicated that CuFeS2@HA show low cytotoxicity at the doses required for photothermal therapy. More importantly, CuFeS2@HA can be used as delivery vehicles for chemotherapy cisplatin(IV) prodrug forming CuFeS2@HA-Pt(IV). Their release profile revealed pH- and glutathione-mediated drug release from CuFeS2@HA-Pt(IV), which may minimize the side effects of the drug to normal tissues during therapy. Subsequent in vitro experiments confirmed that the use of CuFeS2@HA-Pt(IV) provides an enhanced and synergistic therapeutic effect compared to that from the use of either chemotherapy or photothermal therapy alone. The second part of this thesis presents, CuFeS2 nanoparticles functionalized and phase transferred with the help of bovine serum albumin (BSA), for improved solubility, biocompatibility, and physiological stability. The as-prepared CuFeS2@BSA nanoparticles further conjugated with folic acid and chlorin e6 (Ce6), Ce6:CuFeS2@BSA-FA, for tumor-targeted PTT and PDT applications upon single-laser irradiations. The cytotoxicity of the prepared Ce6:CuFeS2@BSA-FA nanoprobe was verified in vitro (using HeLa and HepG2 cells) and in vivo using zebrafish embryos. The combined single-laser-induced phototherapeutic were then performed in vitro using HeLa and HepG2 cells. The results demonstrate combined phototherapy with single-laser-induced approach effectively killed cancer cells and showed higher levels of reactive oxygen species (ROS) generations. The multifunctional applications of our material showed a promising approach for combinational therapy for future biomedical applications to battle cancer, by canceling the use of different wavelength lasers.
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Lai, Yu-Sheng, and 賴郁昇. "Structure and optoelectronic properties of semiconductor CuFeO2." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/13975215638936846270.
Full textAbstract:
碩士亞洲大學
光電與通訊學系
102
This study is focused on the crystal structure, cross-sectional microstructure and optoelectronic properties of p-type semiconductor CuFeO2 films. The films were prepared by using sol-gel method and spin-coating, and then annealing under an argon atmosphere. After annealing at 600 and 620◦C,films adopted mixed CuO and CuFe2O4 phases. The 640◦C -annealed material was pure phase CuFeO2. The root mean square roughness increased with the annealing temperature, and 700◦C -annealed film had a higher value of 15.9 nm. Cross-sectional microstructure images were used to analyze the oxide thicknesses. The film material thicknesses were approximate 110~ 130 nm.CuFeO2 is a wide band gap semiconductor that exhibits transparency over the visible wavelength range. These films are p-type semiconductor material, in which had a lowest resistivity of 2.6 Ω cm.
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Bai, Shi-Yun, and 白世芸. "Synthesis of Delafossite CuFeO2 powders by Chemical Coprecipitation Method." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/4yty29.
Full textAbstract:
碩士國立臺北科技大學
資源工程研究所
105
The objective of this study is to discover a new co-precipitation method for the synthesis of delafossite CuFeO2 powders at 90oC in ambient environment. Tetramethylammonium hydroxide, the capping agent, and ethylenediamine, the chelating agent, are used to control the precipitation rate of copper and iron ions during the formation of the binary metal oxide. All products are measured by using XRD, XPS, and VSM. The XRD analyses show that the products are mainly composed of delafossite CuFeO2 with trace of tenorite (CuO) and maghemite (Fe2O3). XPS spectra also confirm the bivalent states of copper ions in the samples. The magnetization for particles synthesized at low temperature is very weak. Finally, methylene blue was used as the target pollutants in the photocatalytic degradation reaction, 88.3 % of methylene blue was removed in 150 minutes. It was found that CuFeO2 powders could effectively degrade methylene blue. Photocatalytic degradation of methylene blue has been investigated in CuFeO2 aqueous suspensions. 88.3% of methylene blue is decomposed within 150 min using CuFeO2 powders as the catalyst.
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Lee, Yu-Fu, and 李昱甫. "Phase Transformation and Optoelectronic Properties of P-type CuFeO2 Films." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/21029434381320288399.
Full textAbstract:
碩士亞洲大學
光電與通訊學系
103
This study is focused on the phase change and optoelectronic properties of CuFeO2 film as p-type semiconductor. In the experiment, the film was prepared using the sol-gel method and annealed in the controlled argon atmosphere. The films were heated at 500℃~850℃, and the low-temperature phase structures of CuO, CuFe2O4, formed at 550~550℃. The increasing temperature facilitated the formation of CuFeO2. By raising the temperature, copper, iron and oxygen atoms were given enough energy to pile up and form the delafossite structure CuFeO2. The films annealing at 600℃~800℃ formed a single-phase CuFeO2 structure, and annealing at 850℃ formed a secondary-phase structure. As the annealing temperatures increased from 600℃ to 850℃, CuFeO2 had its RMS values increasing from 3.10 to 10.40 nm gradually. The surface of CuFeO2 showed a fiber-like microstructure. With the increase of the temperature, the fiber-like structure grew and thickened. The single phase CuFeO2 had direct band gaps of 3.70~3.78eV. During the Cu-Fe-O phase transformation, the change in structure determined the transmittance and absorption coefficient of the film. The CuFeO2 film absorbed mainly the photons with wavelengths smaller than 400 nm. In analysis based on the Hall effect measurement, the film exhibited hole conduction and thus was identified as p-type film. The optimum electrical properties were identified in the CuFeO2 film annealed at 700℃. The film had its carrier concentration, Hall coefficient, and resistivity measured as 3.753x 1016 cm-3, 1.665 x 102 cm3/C, and 1.196 ohm-cm, respectively.
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CHANG, HUNG-CHENG, and 張宏丞. "Preparation of CuFeO2 thin films using an atmospheric pressure plasma annealing." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/5g3ngn.
Full textAbstract:
碩士國立高雄應用科技大學
化學工程與材料工程系碩士在職專班
104
In this study, Cu-Fe-O thin films were deposited onto a quartz substrate with a sol-gel process and then specimens were annealed using atmospheric pressure plasma between 500℃ and 750℃ with N2-0%O2 to N2-20%O2. Single delafossite-CuFeO2 phase can be formed at 550℃ at N2-3%O2, at 600℃ at N2-3%O2, at 650℃ at N2-3%O2 and N2-5%O2, and at 700℃ at N2-(3-10%)O2. The CuFeO2 thin films displayed two intense Raman active modes at 348-349 cm-1 (Eg) and 687-688 cm-1 (Ag) respectively , the thickness of obtained CuFeO2 thin films were 106-184 nm. The maximum transmittance of CuFeO2 thin the films was approximately 32-42% in the visible region, and three absorption edges at approximately 300、400 and 800 nm region were found . The direct optical bandgap of CuFeO2 thin films was estimated to be 2.9-3.0 eV. Moreover, CuFeO2 thin films have p-type characteristics, which had electrical conductivities of (0.58-5.2)×10-3 S/cm with carrier concentrations of (0.17-4.2)×1014 cm-3 at 600-700℃ with N2-3%O2. In this study, the optoelectronic properties of obtained CuFeO2 thin films are consistent with the literature. However, this method provides a fast and green processing to prepare CuFeO2 thin films.
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FU, JUN-RONG, and 傅俊融. "Preparation of delafossite-CuFeO2 thin films using atmospheric pressure plasma post-annealing." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/vn5q6u.
Full textAbstract:
碩士國立高雄應用科技大學
化學工程與材料工程系博碩士班
102
In this study, the delafossite-CuFeO2 thin films were prepared by atmospheric pressure plasma post-annealing. The pure delafossite-CuFeO2 phase was obtained when the films were annealed with an atmospheric pressure plasma at N2-5%O2. The thickness of CuFeO2 thin film was 80 nm and had having an transmittance of 38-56% in the visible range. The optical bandgap of delafossite-CuFeO2 thin films was 3.1 eV. The XPS spectrum of CuFeO2 thin films showed that the binding energies of the Cu-2p1/2 and Cu-2p3/2 peak were 952.6 eV and 932.7 eV. The Fe-2p spectrum of the CuFeO2 thin films were observed at 723.4 eV and 710.2 eV for 2p1/2 and 2p3/2 peaks, respectively. The O-1s spectrum for the CuFeO2 thin films was centered at 530.2 eV. The XPS confirmed that the chemical state of Cu and Fe were +1 and +3. The electrical conductivity of the thin film was 0.67 S/cm with the carrier concentration of 1.7×1018 cm-3. Furthermore, the p-type characteristics of the films were verified by the Hall-effect measurements. The activation energy of the CuFeO2 was estimated to be 190 meV by the hot-probe measurement. Consequently, an atmospheric pressure plasma post-annealing provides a high efficiency method for the preparation of the delafossite-CuFeO2 thin films.
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Siao, Ting-Fong, and 蕭婷丰. "A new chemical solution synthesis and photocatalytic performance of p-type CuFeO2 powders." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/2huhdm.
Full textAbstract:
碩士國立臺北科技大學
資源工程研究所
106
The objective of this study is to discover a new chemical solution method for the synthesis of delafossite 3R-CuFeO2 powders in ambient environment. In the first method tetramethylammonium hydroxide and sodium hydroxide are used to control the precipitation rate of Cu(I) and Fe(II) ions in the formation of the binary metal oxide. In the second method sodium hydroxide is added alone to control the precipitation rate of Cu(II) and Fe(II) ions. The XRD analyses show that the products are mainly composed of delafossite CuFeO2 with trace of tenorite (CuO) and maghemite (Fe2O3). XPS spectra confirm that some bivalent state of copper are found using the first method for the synthesis of CuFeO2. For the study of photocatalytic performance, 10 ppm methylene blue is used as the target pollutant in the degradation reaction. UV-vis spectra show that, 95% of methylene blue is decomposed in 45 minutes using both of the samples as the catalysts. In order to optimize the synthesis procedure of CuFeO2 preparation, the concentrations of Cu(II) and Fe(II) ions, reaction temperature and reaction time are precisely regulated. The XRD analyses show that the products are mainly composed of 3R and 2H CuFeO2. The valence states of Cu and Fe are confirmed to be +1 and +3 measured by XPS.The compounds exhibit optical band gap around 1.35 eV estimated from UV-vis absorption spectra. The magnetism of the compound is weak paramagnetic. For the photocatalytic performance, 10 ppm methylene blue is used as the target pollutants in the degradation reaction. UV-vis spectra show that 95% of methylene blue is decomposed in 45 minutes using the samples as the catalysts.
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Lin, Tsung-Yung, and 林宗勇. "Photoelectric properties of p-type delafossite-CuFeO2 thin films prepared by sol-gel method." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/03579634741232860805.
Full textAbstract:
碩士國立高雄應用科技大學
化學工程與材料工程系
98
In this thesis, the thin films of Cu-Fe-O were first synthesized by using the sol-gel method and then the films were annealed under controlled atmosphere. When the films were annealed in nitrogen (99.9% and 99.995%) at 600℃~900℃ for 2h, delafossite-CuFeO2 phase with minor CuO and Cu2O appeared. While CuO and CuFe2O4 phase existed at 600℃~900℃ in air annealing. We further use thermodynamics to analyze the changes of Gibbs free energy (ΔG) of formation of delafossite-CuFeO2 for all atmospheres. The ΔG is negative values when the films annealed in nitrogen (99.9% and 99.995%), but the values turns to positive in air annealing. Experimental results are consistent with thermodynamic calculation. The optical bandgap of delafossite-CuFeO2 was about 3.40 eV from the PL measurement. The electrical carriers in delafossite-CuFeO2 was p-type characteristics from thermoelectric measurement. The best conductivity of delafossite-CuFeO2 thin films was 2.96×10-2 S/cm (99.9%) and 3.64×10-2 S/cm (99.995%) as the films annealed in nitrogen.
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Chao, Tzu-Chia, and 趙子嘉. "Fabrication and characteristic of delafossite-type CuFeO2 nanofibers and anisotropic thin film by electrospinning." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/dmr65w.
Full textAbstract:
碩士國立臺北科技大學
材料科學與工程研究所
106
In the investigation of this study divided into two parts. A mixed get solution prepared by cupric nitrate, ferric nitrate and ployvinylpyrrolidone was used as the precursor for electrospinning to fabricate the delafossite-type CuFeO2 nanofibers and anisotropic thin film. First part, CuFeO2 delafossite type nano fibers were fabricated by electrospinning. This experiment explored the effects of annealing temperature, precursor concentration, and ambient annealing on the fiber structure. The results of X-ray diffraction studies (XRD) and field emission scanning electronic microscopy (FESEM) indicated that a pure phase delafossite-type CuFeO2 and perfect nanofibers can be synthesized by annealing at 500C in air for 10 min and 750C in nitrogen for 10 min. The optical properties were measured by UV/VIS spectrometer and the band gap was estimated at 1.4 eV. Furthermore, the specific surface area of the CuFeO2 fibers was 4.33 m2/g, as determined by BET surface area measurements. Second part, High-speed rotating collectors used to prepare the anisotropy thin film. Glass substrates were fixed on the roller with different rotation speed including 100 rpm, 1000 rpm, 2000 rpm, and 3000 rpm for investigation. The results of X-ray diffraction studies (XRD) and field emission scanning electronic microscopy (FESEM) indicated that pure phase of CuFeO2 can be obtained by two-step annealed method. As the rotation speed increased, the fibers presented aligned and more direction. Electrical properties measured near two to three order difference between parallel and vertical direction at 2000 rpm.
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Sobota, Joanna. "Wpływ obróbki cieplno-plastycznej na mikrostrukturę i właściwości użytkowe taśm ze stopu CuFe2." Rozprawa doktorska, 2008. https://repolis.bg.polsl.pl/dlibra/docmetadata?showContent=true&id=5589.
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Sobota, Joanna. "Wpływ obróbki cieplno-plastycznej na mikrostrukturę i właściwości użytkowe taśm ze stopu CuFe2." Rozprawa doktorska, 2008. https://delibra.bg.polsl.pl/dlibra/docmetadata?showContent=true&id=5589.
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YU, SZU-CHIA, and 喻思嘉. "Effect of atmosphere in atmospheric pressure plasma annealing on the formation of CuFeO2 thin films." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/4zgskh.
Full textAbstract:
碩士國立高雄應用科技大學
化學工程與材料工程系博碩士班
106
In this study, delafossite CuFeO2 thin films were deposited onto a quartz substrate with a sol-gel process and then specimens were annealed using an atmospheric pressure plasma between 550 ℃ and 750 ℃ with N2-0%O2 to N2-10%O2. Single delafossite-CuFeO2 phase can be formed at 550 ℃ with N2-0%O2 to N2-3%O2, 600 ℃ with N2-0%O2 to N2-5%O2 and 650 ℃ with N2-3%O2 in the present study. The transmittance of CuFeO2 thin the films was 34-45 % in the visible range, and three absorption edges were found at 300 nm, 400 nm and 800 nm. The direct optical bandgap of CuFeO2 thin films was estimated to be 2.85-3.04 eV. Moreover, the CuFeO2 thin films have p-type semiconductor characteristics, and the thin films had the electrical conductivity of (0.4-7.5)×10-5 S/cm with the carrier concentration of (0.47-22)×1012 cm-3.
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LEE, YUAN-HAN, and 李湲涵. "A New Chemical Solution Synthesis and Photocatalytic Performance of P-type Mg-doped CuFeO2 Powders." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/w8v769.
Full textAbstract:
碩士國立臺北科技大學
資源工程研究所
107
In this study, Mg doped CuFeO2 was prepared via chemical solution method. 2% Mg-doped CuFeO2 powders display good photocatalysis performance. The XRD patterns show that the powders mainly consist of CuFeO2 phase. XPS analyses confirm that the chemical environment of Cu+ and Fe3+. The band gap of the sample is 1.48 eV estimated form UV-vis absorption spectra with the absorption wavelength of 300-700 nm. Photocatalytic degradation of methylene blue has been investigated in a Mg-doped CuFeO2 contained aqueous solution When the solution is exposed to powders under UV light, 98.5% methylene blue can be degraded while 97.5% methylene blue is degraded under visible light irradiation.
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Liang-WeiTu and 塗良瑋. "Hydrothermal fabrication and study of delafossite (CuFeO2) thin films on fluorine doped tin oxide substrates." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/e8vfuz.
Full textAbstract:
碩士國立成功大學
材料科學及工程學系
107
CuFeO2 is a suitable photocatalytic material owing to its narrow band gap in the visible light region. Moreover, CuFeO2 also has a suitable band positions as a photocathode for photoelectrochemical (PEC) water splitting. However, few studies have focused on fabricating CuFeO2 thin films by a hydrothermal method, and the associated physical and chemical properties are still yet to be extensively studied. From the literature, CuFeO2 powders were synthesized in highly basic conditions by hydrothermal methods, however, the condition was not suitable for fabricating CuFeO2 thin films on transparent conducting substrates. In the current study, CuFeO2 thin films were successfully fabricated on the fluorine doped tin oxide (FTO) substrates with the assistance of a seed layer, which was tailored by tuning various deposition parameters. The XRD and SEM results showed the growth of CuFeO2 films. on FTO substrates. The SEM images also ascertained the morphology and uniformity of CuFeO2 films. The XPS was used to determine the constituent elements and chemical states of CuFeO2. The UPS and UV-vis were used to investigate the optical property and band structure of CuFeO2 films. In addition, the photocatalytic activities of CuFeO2 films were studied, including photodegradation of methylene blue dye and PEC water splitting. The CuFeO2 films based on drop casting seed layers exhibited the photodegradation rate constant k of approximately 6.7*10-3/min. The associated photocurrent density was enhanced under illumination, and the measured applied bias photon-to-current conversion efficiency (ABPE) was approximately 0.501 % at applied bias at -0.75 V.
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Urbańczyk-Gucwa, Anna. "Wpływ wydzieleń faz wtórnych na rozdrobnienie struktury stopów CuFe2 i CuCr0,6 odkształcanych metodami SPD." Rozprawa doktorska, 2019. https://repolis.bg.polsl.pl/dlibra/docmetadata?showContent=true&id=57744.
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Urbańczyk-Gucwa, Anna. "Wpływ wydzieleń faz wtórnych na rozdrobnienie struktury stopów CuFe2 i CuCr0,6 odkształcanych metodami SPD." Rozprawa doktorska, 2019. https://delibra.bg.polsl.pl/dlibra/docmetadata?showContent=true&id=57744.
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Huang, Ping-Shuo, and 黃苹碩. "Preparation of delafossite CuFeO2 nanopowder by self-combustion glycine nitrate process and its application on hydrogen generation." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/6yy423.
Full textAbstract:
碩士國立臺北科技大學
材料及資源工程系研究所
100
The delafossite CuFeO2 nanopowder has been successfully prepared by glycine nitrate process (GNP), in this study, the crystal phase varied with glycine/nitrate ratio (GN ratio). A precursor solution was prepared by adding glycine with an aqueous solution of blended (Cu–Fe) metal nitrates in their stoichiometric ratios. In this method, we successful synthesis the low-cost of nanosized CuFeO2 powder. The powder was delafossite structure by X-ray diffraction and Raman, surface area of powder was 6.26 m2/g, as determined by BET surface area measurements. Field emission scanning electron microscopy studies on these powders confirmed their nanosized nature and porous structure.
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Fu, Guan-Wei, and 傅冠維. "Preparation of Delafossite-CuFeO2 Thin Films at Different Oxygen Partial Pressure in the Post-annealing Conditions by Sol-gel Method." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/5d6bkc.
Full textAbstract:
碩士國立高雄應用科技大學
化學工程與材料工程系博碩士班
102
In this study, we discuss the effect of partial oxygen pressure (pO2) and temperature in the post-annealing process on the formation of the delafossite-CuFeO2 thin films. The sol-gel derived films deposited on the quartz substrate were annealed at 500℃ for 1h in air and post-annealed at 500-850℃ in pO2=10-2-5×10-5 atm for 2 and 12 h. CuO and CuFe2O4 phases were found when the specimens were post-annealed below 800℃ in pO2=10-2 atm for 2 h, 600℃ in pO2=10-3 atm for 2 h, and 550℃ in pO2=5×10-5 atm for 2 h. The delafossite-CuFeO2 phase appeared when the specimens were post-annealed at 800℃ in pO2=10-2 atm for 12 h, 600℃ in pO2=10-3 atm for 12 h, and 550℃ in pO2=5×10-5 atm for 12 h. The surface became nanoparticle-like morphology when the thin films had CuO and CuFe2O4 phases. However, the formation of delafossite-CuFeO2 resulted in the granular feature. The thickness of the thin films was approximately 70-95 nm. The transmittance of delafossite-CuFeO2 thin films was between 30% and 60% in the visible region and the optical bandgap of the films was between 3.12 eV and 3.21 eV. The electrical conductivities of delafossite- CuFeO2 thin films were 6.5×〖10〗^(-2)-0.637 S/cm with carrier concentrations of (0.432-22.3)×〖10〗^17 cm-3 and the activation energy of 103-177 meV. The p-type characteristics of the delafossite-CuFeO2 thin films were confirmed by Hall and Seebeck coefficients. Consequently, the partial oxygen pressure and temperature in the post-annealing process play key factor for the formation of delafossite-CuFeO2 thin films.
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CHIANG, KUAN-TING, and 江冠廷. "CuFeO2 photocatalysts prepared by modified ion exchange method and its applications on hydrogen generation via visible-light-driven water splitting." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/87039752711797007365.
Full textAbstract:
碩士國立臺灣科技大學
化學工程系
99
CuFeO2 photocatalyst has a band gap of 1.34 eV, where the light of the entire solar spectrum can almost be fully harvested. Thus, the material is considered as one photocatalyst of great potential to utilize and convert solar energy. In literature, the synthesis of CeFeO2 has to be conducted at high temperatures and it is greatly influenced by the calcination atmosphere. Consequently, it is rather difficult to obtain CuFeO2 in pure phase. In this study, weuse Na [EDTA-Fe]．3H2O as the precursor to obtain α-NaFeO2 by thermal decomposition. An Na+-Cu+ ion exchange reaction is successfully employed to transform the prepared α-NaFeO2 into CuFeO2 photocatalystat a relatively low temperature. Crystal structure and size of CuFeO2 synthesized at different conditions were characterized by XRD, SEM and TEM. Optical properties of CuFeO2 were determined by visible-infrared spectrum. Trends in the carrier recombination of CuFeO2 were characterized by photoluminescence spectrum as well. The results showed thathigh crystallinity of the α-NaFeO2 with layer-structuredcan be synthesized by 0.5 g EDFS．3H2O as the precursor under 1 L/min flow of air at 530 ℃. By studying issues associated with the scale-up of the production process, 3 g EDFS．3H2Ocan be further used to the α-NaFeO2 under 1 L/min flow of 70% O2 at 530 ℃. Furthermore, CuFeO2 can be synthesized by Na+-Cu+ ion exchanging α-NaFeO2 with the molten CuCl at 350 ℃. At this temperature, the sintering effect is less dominant than results at at 500 ℃ and 450 ℃. In fact, the highest photocatalytic activity of CuFeO2 can be successfully obtained by dissolved precursor of mixed α-NaFeO2 and β-NaFeO2. Finally, the photocatalytic CuFeO2 has been successfully demonstrated to be capable of generating hydrogen in an aqueous methanol solution. By integrating a Bi20TiO32 as oxygen production catalyst, which is a parallel work from our laboratory, a Z-scheme water splitting system is realized through a twin reactor with copper wire as the electron transfer medium between two chambers. Hydrogen and oxygen can be successfully produced at the photocathode and photoanode chambers in such a twin reactor system, respectively.
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Chen, Hung-ming, and 陳泓明. "Synthesis of nanocrystalline CuFeO2 by ion-exchange method and its applications on hydrogen generation via visible-light-driven photocatalytic water splitting." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/13078613418993698315.
Full textAbstract:
碩士國立臺灣科技大學
化學工程系
98
Nanocrystalline CuFeO2 has been synthesized successfully by ion-exchanging molten CuCl with layer-structured ??NaFeO2. Crystal structure and domain size of CuFeO2 were characterized by XRD and TEM. Optical properties of CuFeO2 were determined by visible-infrared spectrum as well. In addition, Z-scheme photocatalytic water splitting without electron mediator carried out in a fluidized-bed photocatalyst reactor with as-synthesized CuFeO2 and Bi20TiO32 powder is proposed and measured in the present work. First, nanocrystalline ??NaFeO2 was synthesized successfully by thermal decomposition of EDFS under the air flow of 1 L/min and calcinations at 530 ℃ twice. The grain size of ??NaFeO2 is measured about 5 ~ 10 nm by TEM. High crystallinity of ??NaFeO2 results from suppressing the formation of ??NaFeO2 under sufficient O2 condition. Next, nanocrystalline CuFeO2 was synthesized successfully by ion-exchange method and domain size of CuFeO2 is about 5 ~ 10 nm determined by TEM. Domain boundaries of CuFeO2 result from sintering of grains in molten CuCl. Crystal growth of CuFeO2 is more significant in direction of a axis and b axis when operating temperature of molten CuCl increases. Near-IR absorbance of CuFeO2 increases slightly with increasing dimension of the plane in c axis. The H2 production from the system could not be successfully detected. One reason could be attributed to the serious recombination of photon-generated electrons and holes at the grain boundaries of CuFeO2.
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Lee, Ing-Ping, and 李英平. "Preparation of P-type CuFe1-xCrxO2 thin films by sol-gel method." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/2cz24z.
Full textAbstract:
碩士國立高雄應用科技大學
化學工程與材料工程系碩士在職專班
102
In this study, P-type CuFe1-xCrxO2 thin films were prepared and examined. Firstly, sol-gel solutions with different Fe/Cr ratio were prepared and then deposited onto quartz substrates via spin-coating technique. Subsequently, these specimens were annealed at 500oC in air for 1 hr and were post-annealed at 700oC in N2 for 2 hrs. X-ray diffraction pattern showed that CuFe1-xCrxO2 (0≦x≦1) thin film is delafossite with space group R3m . Cr is possibly to be accomdated in CuFeO2 delafossite structure. Lattice parameter “a” changes linearly, which is consistent with literature. As Cr% increase, film surface becomes porous and transmittance increases. Absorption peak gradually changes from 4.5 eV of CuFeO2 to 3.3 eV of CuCrO2. Optical energy gap linearly decreases from 3.2 eV to 3.06 eV. Moreover, as x increase within CuFe1-xCrxO2 ( 0≦x≦0.3 ), mobility rises from 0.45 cm2 / V-s to 52.6 cm2 / V-s and carrier concentration drops from 1.38 x 1018 cm-3 to 6.02 x 1014 cm-3 singnificantly. This makes conductivity decrases from 9.62 x 10-2 S/cm to 2.51 x 10-3 S/cm.
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GIU, JIN-SHAN, and 邱金山. "Characterization of CoFe and CuFe bimetallic catalyst on CO hydrogenation." Thesis, 1987. http://ndltd.ncl.edu.tw/handle/17345487778031920412.
Full text
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Lu, Chia-Hao, and 呂家豪. "Effects of Weighted Cuffs with different location on Prehensile Performance by Patients with Intentional tremor：Kinematic Study." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/31973651446596302297.
Full textAbstract:
碩士長庚大學
臨床行為科學研究所
92
Abstract Background：Intention tremor has been treated with a variety of procedures including medications, use of weights on the affected limbs or supportive devices. Efficacy study of limb weighting treatment is, however, sparse. This investigation was designed to examine how patients with intentional tremor responded to various weights and locations of weighted cuffs when performing prehensile movements. Methods：Fifteen patients with intentional tremor or dysmetria were instructed to reach forward to open the jar with two kinds of diameter (6cm and 8cm, respectively) under five experimental conditions. Among these conditions, one was the control condition (i.e., no weight). The other four conditions were formed by the crossing of cuff weights (480g and 720g, respectively) and locations (the upper arm or the wrist). Prehensile movement was recorded for study by computerized 3-D motion analysis system. Repeated measures analyses of variance were performed for kinematic variables. Results：Adding various weights on either the wrist or the upper arm significantly improved movement kinematics (reach part) on opening small jar in comparison with the control condition. Conclusion：The results demonstrated limb weighting had beneficial effects on improving prehensile movements in ataxic syndromes. It is possible that appropriate weights for optimally reducing the ataxic syndromes depend on personal neuromuscular characteristics and task parameters. Further research is needed that studies efficacies of various weighting protocols designed in accord with patient characteristics. Various functional tasks can be used for study to assess the generalizability of the present findings.
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Tang, I.-Hsuan, and 唐逸軒. "Hydrothermal Synthesis of CuFe-Layered Double Hydroxides Electrocatalysts for Water Splitting." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/yzmd9u.
Full textAbstract:
碩士國立中央大學
能源工程研究所
106
The development of a low-cost catalyst with dual-functional catalytic effects for water electrolysis to produce hydrogen has been an important research topic. How to improve the catalytic activity of the catalyst is particularly important. In this study, we propose to use transition metals Cu and Fe to synthesize a dual-functional layered double hydroxides (LDHs) catalyst. The hydrothermal method was used for the catalyst preparation. This study includes three stages, from the selection of the substrate to the optimization of the conditions of the precursor solution, and finally the optimization of the CuFe-LDHs catalyst ratio. Surface morphology analysis, elemental composition analysis and electrochemical measurement were used to analyze and explore CuFe-LDHs catalyst. In this study, CuFe-LDHs catalysts were successfully prepared on the surface of nickel foam. The CuFe-LDHs catalyst with a ratio of 1:1 from the SEM image has good coverage and high surface area. Excellent performance in both hydrogen evolution and oxygen evolution reactions (HER: 170 mV @ 10 mA/cm2, Tafel slope 102 mV/dec; OER: 1.57 V@10 mA/cm2, Tafel slope 50 mV/dec). And the catalyst performance is only attenuated by 0.6 % through a 10-hour long-term stability test. The results show that water electrocatalysts with double efficacy can be successfully prepared.
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"Immunomodulatory effect of CUF2 and kuan dong hua in a rat model of house dust mite-induced allergic asthma." 2007. http://library.cuhk.edu.hk/record=b5893446.
Full textAbstract:
Ng, Chor Fung.Thesis (M.Phil.)--Chinese University of Hong Kong, 2007.
Includes bibliographical references (leaves 130-144).
Abstracts in English and Chinese.
ABSTRACT (ENGLISH VERSION) --- p.i
ABSTRACT (CHINESE VERSION) --- p.iv
ACKNOWLEDGEMENTS --- p.vi
TABLE OF CONTENTS --- p.viii
LIST OF TABLES AND FIGURES --- p.xii
ABBREVIATIONS --- p.xiv
Chapter CHAPTER 1. --- GENERAL INTRODUCTION --- p.1
Chapter 1.1 --- Definition of asthma --- p.1
Chapter 1.2 --- Asthma epidemiology --- p.2
Chapter 1.3 --- Pathogenesis of Asthma --- p.3
Chapter 1.3.1 --- Gene-environment interaction --- p.3
Chapter 1.3.2 --- Allergens and atopic sensitization --- p.4
Chapter 1.3.3 --- Other environmental factors --- p.5
Chapter 1.4 --- House dust mite (HDM) --- p.5
Chapter 1.4.1 --- Characteristics of HDM allergens --- p.5
Chapter 1.4.2 --- HDM and asthma --- p.6
Chapter 1.5 --- Pathophysiology of asthma --- p.8
Chapter 1.5.1 --- Airway inflammation --- p.8
Chapter 1.5.1.1 --- Cellular mechanism --- p.8
Chapter 1.5.1.2 --- Characteristics of chronic inflammation --- p.9
Chapter 1.5.1.3 --- Inflammatory cells in airway inflammation --- p.10
Chapter 1.5.1.3.1 --- Mast cell --- p.10
Chapter 1.5.1.3.2 --- Macrophages --- p.11
Chapter 1.5.1.3.3 --- T lymphocytes --- p.12
Chapter 1.5.1.3.4 --- Eosinophils --- p.12
Chapter 1.5.1.3.5 --- Epithelial cells --- p.13
Chapter 1.5.1.4 --- Cytokines in asthma --- p.14
Chapter 1.5.1.4.1 --- Inflammatory cytokines --- p.14
Chapter 1.5.1.4.1.1 --- Interleukin-4 --- p.14
Chapter 1.5.1.4.1.2 --- Interleukin-5 --- p.14
Chapter 1 5.1.4.1.3 --- Interleukin-6 --- p.15
Chapter 1.5.1.4.1.4 --- Granulocyte Monocyte Colony Stimulating Factor (GM-CSF) --- p.15
Chapter 1.5.1.4.1.5 --- Tumor Necrosis Factor-α (TNF-α) --- p.16
Chapter 1.5.1.4.2 --- Anti-inflammatory cytokines --- p.17
Chapter 1.5.1.4.2.1 --- Interleukin-10 --- p.17
Chapter 1.5.1.4.2.2 --- Interferon-γ(IFN-γ) --- p.17
Chapter 1.5.2 --- Airway hyperresponsiveness (AHR) --- p.18
Chapter 1.5.3 --- A irway remodeling --- p.19
Chapter 1.6 --- Asthma therapy --- p.21
Chapter 1.6.1 --- β2-agonists --- p.21
Chapter 1.6.2 --- Cromolyn and nedocromil --- p.21
Chapter 1.6.3 --- Theophylline --- p.22
Chapter 1.6.4 --- Leukotriene modifiers --- p.22
Chapter 1.6.5 --- Corticosteroids --- p.23
Chapter 1.7 --- Traditional Chinese Medicine --- p.24
Chapter 1.7.1 --- Introduction --- p.24
Chapter 1.7.2 --- Traditional Chinese Medicine (TCM) --- p.24
Chapter 1.7.3 --- "Chinese herbal formula, CU Formula 2 (CUF2) and Kuan Dong Hua" --- p.26
Chapter 1.8 --- Objectives of our studies --- p.28
Chapter CHAPTER 2. --- ESTABLISHMENT OF A HDM-INDUCED ASTHMATIC ANIMAL MODEL IN SD RATS --- p.32
Chapter 2.1 --- Introduction --- p.32
Chapter 2.2 --- Materials and methods --- p.33
Chapter 2.2.1 --- Buffers and solutions --- p.33
Chapter 2.2.2 --- Animals --- p.33
Chapter 2.2.3 --- Preparation of aluminum hydroxide gel --- p.34
Chapter 2.2.4 --- HDMAllergen --- p.34
Chapter 2.2.5 --- Sensitization Procedure --- p.35
Chapter 2.2.6 --- Intratracheal instillation challenge --- p.35
Chapter 2.2.7 --- Bronchoalveolar lavage (BAL) and BAL Cell counting --- p.36
Chapter 2.2.8 --- Lung Histopathological Analysis --- p.37
Chapter 2.2.9 --- Measurement of cytokine and chemokine by Enzyme-Linked Immunosorbent Assay (ELISA) --- p.39
Chapter 2.2.10 --- Statistical Analysis --- p.40
Chapter 2.3 --- Results --- p.41
Chapter 2.3.1 --- Cellular Analysis of BALF --- p.41
Chapter 2.3.2 --- Histopathology --- p.42
Chapter 2.3.3 --- Cytokine and chemokine --- p.43
Chapter 2.4 --- Discussion --- p.44
Chapter CHAPTER 3. --- IMMUNOMODULATORY EFFECT OF CUF2 AND KUAN DONG HUA IN A RAT MODEL OF HDM-INDUCED ASTHMA --- p.65
Chapter 3.1 --- Introduction --- p.65
Chapter 3.2 --- Materials and methods --- p.67
Chapter 3.2.1 --- Herbal materials and extraction method --- p.67
Chapter 3.2.2 --- "Antigen sensitization, challenge, and treatment" --- p.68
Chapter 3.2.3 --- Bronchoalveolar lavage and cell differential counts --- p.69
Chapter 3.2.4 --- Histological Studies --- p.69
Chapter 3.2.5 --- Measurement of BALF cytokines and chemokines --- p.70
Chapter 3.2.6 --- "Body weight, thymus index and spleen index" --- p.70
Chapter 3.2.7 --- Statistical analysis --- p.70
Chapter 3.3 --- Results --- p.71
Chapter 3.3.1 --- Effect of herbs and DXA on total cells and eosinophils in BALF --- p.71
Chapter 3.3.2 --- Effect of herb and DXA on lung histology --- p.72
Chapter 3.3.3 --- Effect of herbs and DXA on cytokine and chemokine level in BALF --- p.73
Chapter 3.3.4 --- "Effect of herb and DXA on body weight, thymus index and spleen index" --- p.75
Chapter 3.4 --- Discussion --- p.77
Chapter CHAPTER 4. --- IMMUNOMODULATORY EFFECT OF KUAN DONG HUA ON HUMAN MAST CELLS (HMC-1) --- p.109
Chapter 4.1 --- Introduction --- p.109
Chapter 4.2 --- Materials and methods --- p.110
Chapter 4.2.1 --- Reagents --- p.110
Chapter 4.2.2 --- Cell line and Cell Culture --- p.111
Chapter 4.2.3 --- Herb and extraction procedure --- p.111
Chapter 4.2.4 --- Cell Viability Assay --- p.112
Chapter 4.2.5 --- Assay of cytokine secretion --- p.113
Chapter 4.2.6 --- Quantitative Analysis of cytokines --- p.113
Chapter 4.2.7 --- Bacterial endotoxin contamination --- p.114
Chapter 4.2.8 --- Statistical analysis --- p.115
Chapter 4.3 --- Results --- p.116
Chapter 4.3.1 --- Effect of Kuan Dong Hua on cell viability of HMC-I --- p.116
Chapter 4.3.2 --- Effect of Kuan Dong Hua on cytokine release from HMC-I --- p.116
Chapter 4.3.3 --- Effect of endotoxin contamination in the extract --- p.117
Chapter 4.4 --- Discussion --- p.118
Chapter CHAPTER 5. --- GENERAL CONCLUSION --- p.125
Chapter 5.1 --- Conclusion --- p.125
Chapter 5.2 --- Limitations of this study and Future work --- p.128
REFERENCES --- p.130
APPENDICES --- p.145
Appendix A. Wright-Giemsa Stain for cytospin preparations --- p.145
Appendix B. Hematoxylin & eosin (H&E) staining --- p.145
Appendix C. Congo Red staining --- p.146
Appendix D. Periodic acid-Schiff (PAS) staining --- p.146